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Full text of "The Cambridge Natural History"

TREE-KANGAROOS                                135

blance to the English hare," and L. leporoides was so called by
Gould on account of general appearance as well as face.
Dorcopsis has shorter hind-legs than Macropus, and a naked
muffle. The ears are small. The structure of D. luctuosa has
been studied by Garrod,1 who pointed out the existence of four
enlarged hair follicles on the neck near the mandibular sym-
physis. These are, however, represented in the next genus
Dendrolagus, and occur also in Petrogale. The limbs are not so
disproportionate as in Macropus, and the tail is naked at the tip.
Dorcopsis and the next genus to be described, Dendrolagus,
differ from Macropus and its immediate allies, Petrogale and Lagor-
chestes, in a number of anatomical points. In the first place, the
premolars are twice the size of those of Macropus, and they have
a characteristic pattern not observable in the Kangaroos. This
consists of a median ridge (the whole tooth being rather prismatic
in shape), with lateral ridges at right angles to it. The upper
canines are developed, but are minute.
The stomach is not quite like that of Macropus, though built
upon a similar plan. The blind cardiac extremity is a single, not
a double cul-de-sac.; in this it is like that of Petrogale. The dis-
tribution of the squamous, white, oesophageal epithelium is very
much like that of Dendrolagus. In both genera the orifice of the
oesophagus into the stomach is guarded by two strong longi-
tudinal folds, which run for some distance towards the pylorus.
In Dendrolagus, at any rate, this tract is bordered on each side
by glandular patches. In Dendrolagus, moreover, the squamous
epithelium does not extend into the cardiac cul-de-sac. This
latter is separated from the rest of the stomach by two slightly
diverging folds, which are faintly represented in Petrogale and in
ITalinaturus. In the last two genera the folds surrounding the
oesophageal orifice are but slightly represented ; better in Hal<ma-
turus than in Petrogale. But there are not the patches of glands
already referred to. The small intestine of Dorcopsis is 97
inches in length, the large being 32, i.e. proportionately long, as
in Marsupials generally. The small caecum (2-^ inches) is not
sacculated.
The spleen is Macropodine, being T-shaped or Y-shaped. The
differences between Dorcopsis and the evidently closely allied
Dendrolagus will be further considered under the description of
1 Proc. Zool. Soc. 1875, p. 48.